If the body of a commit message contains a diff that is not indented
then "git am" will treat that diff as part of the patch rather than
as part of the commit message. This allows it to apply email messages
that were created by adding a commit message in front of a regular diff
without adding the "---" separator used by "git format-patch". This
often surprises users [1-4] so add a check to the sample "commit-msg"
hook to reject messages that would confuse "git am". Even if a project
does not use an email based workflow it is not uncommon for people
to generate patches from it and apply them with "git am". Therefore
it is still worth discouraging the creation of commit messages that
would not be applied correctly.
A further source of confusion when applying patches with "git am" is
the "---" separator that is added by "git format patch". If a commit
message body contains that line then it will be truncated by "git am".
As this is often used by patch authors to add some commentary that
they do not want to end up in the commit message when the patch is
applied, the hook does not complain about the presence of "---" lines
in the message.
Detecting if the message contains a diff is complicated by the
hook being passed the message before it is cleaned up so we need to
ignore any diffs below the scissors line. There are also two possible
config keys to check to find the comment character at the start of
the scissors line. The first paragraph of the commit message becomes
the email subject header which beings "Subject: " and so does not
need to be checked. The trailing ".*" when matching commented lines
ensures that if the comment string ends with a "$" it is not treated
as an anchor.
[1] https://lore.kernel.org/git/bcqvh7ahjjgzpgxwnr4kh3hfkksfruf54refyry3ha7qk7dldf@fij5calmscvm
[2] https://lore.kernel.org/git/ca13705ae4817ffba16f97530637411b59c9eb19.camel@scientia.org/
[3] https://lore.kernel.org/git/d0b577825124ac684ab304d3a1395f3d2d0708e8.1662333027.git.matheus.bernardino@usp.br/
[4] https://lore.kernel.org/git/CAFOYHZC6Qd9wkoWPcTJDxAs9u=FGpHQTkjE-guhwkya0DRVA6g@mail.gmail.com/
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we install Git we also install a set of default templates that both
git-init(1) and git-clone(1) populate into our build directories. The
way the pristine templates are laid out in our source directory is
somewhat weird though: instead of reconstructing the actual directory
hierarchy in "templates/", we represent directory separators with "--".
The only reason I could come up with for why we have this is the
"branches/" directory, which is supposed to be empty when installing it.
And as Git famously doesn't store empty directories at all we have to
work around this limitation.
Now the thing is that the "branches/" directory is a leftover to how
branches used to be stored in the dark ages. gitrepository-layout(5)
lists this directory as "slightly deprecated", which I would claim is a
strong understatement. I have never encountered anybody using it today
and would be surprised if it even works as expected. So having the "--"
hack in place for an item that is basically unused, unmaintained and
deprecated doesn't only feel unreasonable, but installing that entry by
default may also cause confusion for users that do not know what this is
supposed to be in the first place.
Remove this directory from our templates and, now that we do not require
the workaround anymore, restructure the templates to form a proper
hierarchy. This makes it way easier for build systems to install these
templates into place.
We should likely think about removing support for "branch/" altogether,
but that is outside of the scope of this patch series.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
